Predicting the Processability of Polymers in a Twin-Screw Extruder: CFD Simulation and Experimental Validation

Twin-screw extruders are widely used to manufacture various polymers for large-scale processing in the industry. However, new polymers and modified polymers that have not been manufactured before would require experiments to undergo a trial-and-error phase that is time-consuming and costly. In this study, a computational fluid dynamics (CFD)-based model was developed in Ansys Polyflow to describe the extrusion process behavior and predict the processability of different polymers. The optimum processing conditions for polypropylene (PP) and polylactic acid (PLA) acquired from trial-and-error experiments were simulated, and the resulting torque was validated using experimental data. The model was in good agreement with the results of the experiment with a less than 10% difference. It was further validated by determining its effectiveness in calculating the torque for rotation speed and feed rates where the barrel is sufficiently filled with the polymer. Moreover, the investigation also showed that the model has successfully determined the processability of semicrystalline polymers.